This invention provides a protective mask and a method of manufacture thereof, and more particularly, a protective mask of simple but new structure and a method of manufacturing the new pulp fiber structure which is a vital constituent of the mask. Poisonous gas such as carbon monoxide, which is emanated, for example, when dwelling houses are on fire, is absorbed by said new pulp fiber structure while the gas passes through it. Further according to the present invention, the pulp fiber structure has a first pulp fiber layer having gas absorbents mixed therewith in a preferable manner, and a second pulp fiber layer having a skin crust which is integrally continuous to pulp fibers on the surface of one side, the skin crust being fabricated by hydrating, pressing and drying that surface. After these two layers are superposed, the pulp fiber structure is wrapped to form on an integral structure which is then suitably included in a mask body of preferably non-woven fabric.
In case the of fires in dwelling houses, hotels, inns and other business facilities, there have been reported instances where people died during a period of time before the flames reached the ceiling, because people were unable to move a short distance of three to four meters to get out. In evacuating, a short difference of time and distance may affect human life fatally, and one decisive factor is the poisonous nature of smoke and gas emanated by fire. Smoke caused by fire is, as generally understood, characterized by minute particles of various materials and gas emanated by thermal disintegration and burning and hanging in the air.
Recently, a change in the nature of smoke, due to changes in architectural materials, causes further problems as the smoke at the scene of a fire may now contain carbon monoxide, carbon dioxide, hydrogen cyanide and so forth.
It is also known that when a thick bed quilt of cotton or synthetic fiver burns, a large quantity of carbon monoxide is created. When a person inhales it, the oxygen supplying function of hemoglobin in human blood is hindered, so disturbing the brain and nervous system, causing fatal carbon monoxide poisoning. Further, when silk, wool, nylon carpet or urethane mats burn, hydrogen cyanide gas fumes are given off. When a person inhales even a small quantity of such a gas, they lose consciousness, fall into a fit of convulsions, stop breathing and die. Statistics teach that the mortality rate due to the above described poisonous gas is over 80%.
Numerous protective devices, such as automatic breath protection devices, smoke masks and the like for removing poisonous gas caused by fire, are on the market. However, standards on the safety, adaptability and anti-gas effect established by competent authorities are not clear, so that if the manner of use of such devices is mistaken, there is a danger to human body and life.
There is also provided a gas mask combined with a gas absorbing can for removing poisonous gas. Gas Mask Standard lists five classes and Japanese Industrial Standard lists nine classes depending on the kind of poisonous gas to cope with. Various gas absorbents are filled in nine kinds of such cans. These cans are used in industrial circles, and the users are required to undergo thorough training and expected to have experience so that they may become familiar with the kind of can and absorbent to be used. Such is a system not suitable for use by the ordinary person.
There is a problem if ordinary people always keep such protective devices in stock in anticipation of a fire breaking out in their dwelling house. Even if a person has such a device ready, there is a problem, if the person does not know how to use the device, for them to be able to judge instantly the adaptability or the kind of device when a fire actually breaks out.
Further, there is a risk that the person may lose too much time in trying to wear the device, and so is eventually exposed to death. There may also be a secondary danger resulting from the use of these devices.
The object of the present invention is to solve the above described problems found in the conventional products, and more particularly, to offer a safe and simplified protective mask which may be always stocked in any dwelling house to be worn easily by anybody at a time of fire emergency, in order that the person may evacuate to safety without being exposed to danger caused by the poisonous gas.
The above described problems are solved according to the present invention by offering a protective mask having a first pulp fiber layer in which pulp fibers are lying over or under one another without twining, and gas absorbents are mixed in gaps between the pulp fibers. A second pulp fiber layer, in which pulp fibers are lying over or under one another without twining, has a skin crust, having no gaps between fibers, formed on the surface of one side thereof by a process of hydrating, pressing and drying of fibers. A pulp fiber structure is made up by placing the first pulp fiber layer, with a portion thereof downwards having more gas absorbents than the remaining portion, on a surface of the second pulp fiber layer not having the skin crust.
According to another aspect of the present invention, there is provided a method of manufacturing a protective mask comprising the steps of transforming a pulp sheet to pulp fibers through beating by rotating blades of a hammer mill and causing said pulp fibers, by an air flow formed by said rotating blades, to move and temporarily stay in a dead air space within an apparatus defined by an outer wall, sending to, and causing to stay at, said dead space gas absorbents, together with air, by a jet device, causing said pulp fibers and gas absorbents to fall down and pile on a sheet, preferably a tissue paper, placed on a moving belt to move together therewith to form a first pulp fiber layer.
According to yet another aspect of the present invention, there is provided a method of manufacturing a protective mask comprising the steps of transforming a pulp sheet to pulp fibers through beating by rotating blades of a hammer mill and causing pulp fibers, by an air flow formed by said blades, to move and temporarily stay in a dead air space within an apparatus defined by an outer wall, and causing said pulp fibers to fall down and pile on a tissue paper or like sheet placed on a moving belt to move together therewith. Then hydrating, pressing and drying only one side of a layer of said pulp fibers to form a skin crust integrally continuous to the layer of the pulp fibers.
According to the present invention, a pulp fiber structure is formed by superimposing a first pulp fiber layer, having gas absorbents mixed therewith, on a second pulp fiber layer having a skin crust, the pulp fiber structure is then included in a mask body of non-woven fabric, for example cut out in a mask shape. The mask body preferably has pleats and an aluminum piece. Poisonous ingredients of smoke entering the first pulp fiber layer are absorbed by the gas absorbents, and smoke less the poisonous gas, after having been absorbed the the pulp fibers, finally passes through the skin crust by which remaining poisonous elements are caught and removed.
According to the method of manufacture of the first pulp fiber layer of this invention, a pulp sheet is crashed, i.e. struck, by rotating blades of the hammer mill, transformed into pulp fibers which are caused to move and hang in the air at the dead air space by an air flow formed by the rotation of the blades while gas absorbents are directed to the dead air space by the jet device to be mixed with pulp fibers, then the pulp fibers and gas absorbents fall down and pile on the tissue paper on the moving belt to offer the first pulp fiber layer.
In preparing the second pulp fiber layer, supplying of gas absorbents by the jet device in the above described method is omitted, and the pulp fibers alone are caused to fall down and pile on the tissue paper on the moving belt, then only the upper portion of the pulp fiber layer is hydrated, pressed and dried to form the skin crust. This upper portion becomes an outer, or lower, portion in the assembled protective smoke mask.
Other objects, features and advantages of the present invention will become more fully apparent from the following detailed description of the preferred embodiments, the appended claims and the accompanying drawings.